Spark-plug for internal-combustion engines.



K. FoRBEsi- "SEARK PLUG FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED AUG23| 19l6.

Patented Nov. 20, 1.91?.

LQYJE.

KINGSTON FORBES KINGSTON FORBES, OF FLINT, MICHIGAN.

SPARK-PLUG FOR INTERNAL-COMBUSTION ENGINES.

' Specification of Letters Patent.

1,247,102., Patented Nov. 20, 191'?.

Application led August 23, 1916. Serial No. 116,515.

Michigan, have invented certain new and therein by any preferred means,the lower 60 useful Improvements in Spark-Plugs for end of saidelectrode projecting below the Internal-Combustion Engines, of which thelower end face of the plug. As thus far defollowing is a specification,reference being scribed, the spark plug is quite common in had to the'accompanying drawings. the art, and has been generally adopted in Thisinvention relates to an improved preference to the sectional spark plugwhich, 65 spark plug for internal combustion engines though it admits ofbetter and more thorand has for its primary object to provide oughcleaning, yis impractical in use owing improved means for detachablyconnecting to the fact that it is almost/impossible to the outerelectrode to the plug shell-so as to make the plug gas-tight. On theother hand,

afford ready access to the parts o f the plug a. plug of the latestimproved type-having 70 for the purpose of removing carbon deposits. theinseparably connected porcelain body It is another important object ofthe inand outer metal shell is hard to clean, as the vention to providea detachable electrode outer electrode is permanently connected to whichis so constructed and mounted in the the shell so that access to thevarious crevices plug shell that the same will be held against withinwhich carbon inds lodgment cannot 75 all possibility of accidentaldisplacement by be readily obtained. the wall of the engine cylinder inwhich the It is, therefore, the primary purpose of plug is threaded. thepresent invention to devise an improved It is a further general objectof my invendetachable outer electrode which may be tion to simplify andimprove the construcvery easilyand quickly disconnected from 80 tion ofengine spark plugs and increase the the spark plug shell or appliedthereto, operating eliiciency and serviceability therewhereby the abovenoted objection to the of in practical use, though without increas#inseparable plug construction is obviated. ing the manufacturing cost ofthe plug to To this end, I provide longitudinally eX- 80 any materialextent. tendingvgrooves 9 at diametri'cally opposite 85 With the aboveand other objects in view, points in the periphery of the shell 6, saidmy invention consists in the novel features grooves extending throughthe threaded secof construction, combination and arrangetion 7 `of saidshell. An opening 10 is ment of parts to be hereinafter more fullyformed in the shell wall at the inner end of described, claimed andillustrated in the aceach of these grooves or channels 9. 90 companyingdrawing, in which, The detachable electrode 11 is of U-shaped Figure 1is a vertical sectional view of a form, the parallel end portions 12thereof spark plug, illustrating the preferred embeing suficientlyresilient to enable the same bodiment of my invention and showing the tobe sprung apart or away'from each other.

40 same mounted in a cylinder wall; The extremities of the said portions12 of 95 Fig. 2 is a horizontal section taken on the the electrode areangularly disposed to proline 2--2 of Fig. 1; vide inwardly proJectinglugs 13. In apply- Fig. 3 is a side elevation of a part of the ing thedetachable electrode to thespark spark plug shell, the electrode beingdeplugshell, theend portions 12 are sprungrv tached therefrom; and apartsuiiciently to enable the lugs 13 to be 1'00 Fig. 4 is a detailperspective view of the engaged in the grooves or channels 9anddetachable electrode. said electrode is then forced longitudinallyReferring in detail to the drawing, 5 upon the shell until the lugssnapinto the designates the core of porcelain or other openings 1Q. 1 Thegrooves 9 are suiiciently suitable material constituting the body ofdeep to entlrely receive the end portions' 12 105 the plug, and 6 themetallic shell Within of the electrode. The intermediate portion whichthe porcelain core is fitted and permaof the electrode 11 extendsdlametrically nently xed or secured, in any approved across the bottomof the shell 1n spaced relamanner. The reduced stem of theshell 6 hastion thereto and in spaced relation to the an exteriorly threadedportion 7 for engagelower vend .of the electrode 8, the space be- 110 Toall lwhom it may concern:

Be it known that I, KINGSTON FORBES, a citizen of the United States,residing at Flint, in the county of Genesee and State of ment inthethreaded opening of the cylinder wall shown at C. The electrode 8receiving the vpositive current, extends centrally through the porcelainbody 5 and is secured .wall of the cylinder C, the end portions l2 aredisposed ywithin the opening in the cylinder Wallso that theyarepositively held within the grooves 9 against displacement. When it isdesired to clean the plug, the same is removed from the cylinder walland the end portions l2 of the electrode ll then sprung outwardly so asto disengage the lugs 13 from the openings 10. The electrode 11 may thenbe shifted longitudinally and entirely disconnected from the spark plug.Access may now be readily had to the various crevices between theporcelain body and' the shell of the plug with a knife or other suitabletool and such carbon as has been deposited therein removed. Thus, theserviceability and efficiency of the plug in practical operation may bemaintained, and the thorough cleaning of the plug very easily andquickly accomplished. lt is, of course, apparent that the illustratedplug construction is simply indicative of that general type ofinseparable spark plug to which my invention is particularly applicable,and it is to be understood that the detachabley electrode may as readilybe employed in connection with various other plug constructions of thisgeneral type. rllhe device is also susceptible of considerablemodification in the form, construction and arrangement of its severalfeatures and l, therefore, reserve the privilege of adopting all suchlegitimate changes as may be fairly embodied within the spirit and scopeof the invention as claimed.

Having thus fully described my invention, what l desire to claim andsecure by Letters Patent is l. rlrhe combination with a spark plugshell, of an electrode having spaced, resilient portions to clampinglyengage the eX- terior of the shell at diametrically opposite points,each spaced portion of the electrode being provided with terminal meansfor interlocking connection with the shell. i

2. The combination with a spark plug shell having diametrically opposedopenings in its wall, of an electrode having spaced, resilient portionsto clampingly engage the exterior of the shell at diametrically oppositepoints, and saidspaced portions having terminal means for engagementthrough said openings.

3. The combination with a spark plug shell having openings atdiametrically opposite points in its wall, of an electrode contecnicasisting of a resilient, metal rod bent to provide spaced, parallelportions adapted to clampingly engage the exterior of the shell, each ofsaid parallel portions having an inwardly projecting terminal 'lugformed thereon for engagement through one of the openings in the shell.

l. The combination with a spark plug shell, of an electrode consistingofy a U- shaped rod having resilient end portions adaptedyto clampinglyengage the exterior of the spark plug shell at diametrically oppositepoints, the terminals of the electrode being wholly disposed within theopening in the cylinder wall and held by the wall and the spark plugshell against relative movement.

5. As an improved article of manufacture, a spark plug electrode formedfrom a resilient rod bent to provide spaced, yieldable portions adaptedfor detachable clamping engagement against opposite sides of the sparkplug shell, each of said portionsy having an inwardly projectingterminal lug for locking engagement with the shell.

6. The combination with aspark plug having an insulating body'providedwith an electrode and a metal shell within which said body ispermanently secured; of a complementary electrode having spacedresilient portions for detachable clamping engagement with the shell ofthe spark plug.

7. 'llhe combination with a spark plug having an insulating bodyprovided with an electrode and a metal shell within which said body isApermanently secured, of a complementary electrode ofsubstantiallyU-shaped form, the spark plug shell being 'provided upon'diametricallyopposite sides with longitudinal grooves to receive the terminalportions ofk said electrode, said portions oiE the electrode being heldwithin the grooves titi lid@

against displacement by the wall of the engine cylinder.

8, rllhe combination with a vspark plug il@ having an insulating bodyprovided with an electrode and a metal shell within which said body ispermanently secured, of a complementary electrode of substantially U-shaped form having spaced, parallel, resili- 11a ent portions, the sparkplug shell being provided u on diametrically opposite sides with longituinal grooves in which the yieldable portions of the electrode forclampingengagement, saidy yieldable portions of the l2@ electrode beingheld within said grooves by the wall of the engine cylinder.

9. 'llhe combination with a spark plug having an insulating bodyprovided with an electrode and a metal Shell within which said body ispermanently secured, of a complementarv, detachable electrode ofsubstantiallv lll-shaped form having spaced, parallel, resilientportions provided with inwardly projecting terminal lugs, the spark plugshell il? immo l 3;,-

being provided with longitudinal grooves on In testimony .whereof 1hereunto aiiix my dialnetricaliy opposite slllde anddan opening.signature i'nthe presence of vtwo Witnesses.

at t e inner end of eac o sai grooves to receive the terminal 'lugs -onAsaid electrode KNGSTON'FORBES 5 the terminal lugs of the electrode beinhei Y Witnesses: Y v Within said openings by the wall of .t e en.- FRANKE. RILEY, gine cylinder. v A. E. Bow 1 :4. e

